Key Facts


17P/Holmes is a mid-sized comet whose orbit features a relatively short period, low inclination, and is controlled by Jupiter's gravitational effects. NASA JPL has not classified 17P/Holmes as potentially hazardous because its orbit does not bring it close to Earth.

17P/Holmes orbits the sun every 2,520 days (6.90 years), coming as close as 2.07 AU and reaching as far as 5.19 AU from the sun. 17P/Holmes is about 3.4 kilometers in diameter, making it larger than 99% of asteroids, comparable in size to the island of Manhattan.

No Close Approaches

17P/Holmes's orbit is 1.07 AU from Earth's orbit at its closest point. This means that there is an extremely wide berth between this asteroid and Earth at all times.

Orbital simulations conducted by NASA JPL's CNEOS do not show any close approaches to Earth.

Images and Observations

17P/Holmes's orbit is determined by observations dating back to Jan. 4, 2011. It was last officially observed on Jan. 22, 2023. The IAU Minor Planet Center records 2,211 observations used to determine its orbit.

Accessibility and Exploration

This comet is not considered a viable target for human exploration by the NHATS study.

Similar Objects

These objects have orbits that share similar characteristics to the orbit of 17P/Holmes:



   or view a random object

Orbital Elements

  • Epoch: 2457680.5 JD
  • Semi-major axis: 3.626 AU
  • Eccentricity: 0.4302
  • Inclination: 19.07°
  • Longitude of Ascending Node: 326.77°
  • Argument of Periapsis: 24.74°
  • Mean Anomaly: 133.79°

Physical Characteristics

  • Diameter: 3.42000 km
  • Magnitude: 9.4

Derived Characteristics

  • Orbit Period: 2,520 days (6.90 years)
  • Avg. Orbit Speed: 15.65 km/s
  • Aphelion Distance: 5.19 AU
  • Perihelion Distance: 2.07 AU

Map Comparison

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Orbit Simulation

Sky Map

The position of 17P/Holmes is indicated by a ◯ pink circle. Note that the object may not be in your current field of view. Use the controls below to adjust position, location, and time.

Size Rendering

The above comparison is an artistic rendering that uses available data on the diameter of 17P/Holmes to create an approximate landscape rendering with Mount Everest in the background. This approximation is built for full-resolution desktop browsers. Shape, color, and texture of asteroid are imagined.